Control valving system for flame spraying apparatus



Jan. 15, 1963 c. K. WILSON ETAL 3,073,528

CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS Filed March 28, 1958 6 Sheets-Sheet 1 INVENTORS CHARLES K WILSON WALTER A S/EBE/N ATTORNEYS Jan. 15, 1963 c. K. WILSON ETAL ,0

CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS Filed March 28, 1958 6 Sheets-Sheet 2 INVENTOR CHARLES K. WILSON -WALTER A. S/E'BE/N ATTORNEYS Jan. T5, 1963 c, K, w|| soN ETAL 3,073,528

CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS Filed March 28, 1958 6 Sheets-Sheet 3 INVENTORS CHARLES K. WILSON 37d WALTER A. S/EBE/N BY m g, I M a I g '3 A6. 1%TORNEYS Jan. 15, 1963 c. K. WILSON ETAL 3,073,523

CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS Filed March 28, 1958 s Sheets-Sheet 4 INV EN TORS CHARLES K. W/LS WALTER A. S/EBE 6 Ll-21 ZmS Jan. 15, 1963 c. K. WILSON ETAL 3,073,528

CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS Filed March 28, 1958 6 Sheets-Sheet 5 QWNR ah/U QG M .8m 0 & 8% 20 s 5 R m m N R E o W i N v, w

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CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS Filed March 28, 1958 .6 Sheets-Shee t a GUI:

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CHARLES K. WILSON WALTER A. S/EBE/N United States Patent 3,073,528 CONTROL VALVING SYSTEM FOR FLAME SPRAYING APPARATUS I Charles K. Wilson, East Williston, and Walter A. Siehein,

Wantagh, N.Y., assignors to Metco Inc., a corporation of New Jersey Filed Mar. 28, 1958, Ser. No. 724,678 17 Claims. (Cl. 23979) This invention relates to a control system for 'controlling the flow of gases to an apparatus for applying heatfusible coatings on solid objects.

An apparatus for applying heat-fusible coatings is generally referred to as a heat-fusible material spray gun, and is often referred to as a metal spray gun, although the materials to be sprayed are sometimes metal oxides (usually referred to as ceramics), as Well as relatively pure metals.

The heat-fusible material spray guns generally have means for feeding the heat-fusible spray material to a heating zone and means for feeding a'combustible gas and a combustion-supporting gas to said heating zone under conditions of combustion, so as to provide sufiicient heat to melt, or at least heat-soften, said heat-fusible material. Gas blasting means, either directly associated with said:

combutsible gas and said combustion-supportinggases, or

alternatively comprised of a separate blasting gas, is pro vided for the purpose of conveying the heat-softened particles to the surface to be coated. The blasting gas used is frequently air and, in cases where the heat-fusible spray material is conveyed to the heating zone in solid form,

such as in the form of rod or wire, provides at least some of the energy for atomizing the solid spray material in the heating Zone into finely divided particles.

Heat-fusible material spray guns are usually either of the wire type or powder type. In the wire type spray guns, the heat-fusible material is fed to the heating zone in the form of a relatively solid rod or Wire. In some cases powdered materials are compacted into rods or wire for this purpose by sintering, and in other cases powdered materials are compacted into rod orwire form by the use of a binding material which disintegrates'in the heating zone of the gun. In the powder type spray guns, the heat-fusible material to be sprayed is fed. to the heating zone in the form of powder or finely divided material.

Heat-fusible material spray guns have conventionally j been provided with a valve in each of the gas feed lines to the gun. In the more modern guns,'the valves for each"v of the gases fed to the gun are frequently connected together for simultaneous operation, either by mechanical interlock of separate valve mechanisms or by combining the two or three valves required as a separate set of ports in a single tapered plug valve. To properly control the How of gases to the gun for the lighting operation of-the gun, it has been common practice to construct and arrangesuch valves, so that the flow of each of the gases involved increases gradually and in proper proportion during the lighting operation. For instance, where a single tapered plug valve is used for the control of combustible gas, combustion-supporting gas, and blast gas, it is common practice to provide such plug valve with three ports and to cut grooves (known as bleeders) of varying sizes at the entrance to the ports, so that as the plug valve is rotated, the various gases start to flow at low flow rates and gradually increase their flow rates in proper proportion to maintain combustion atter lighting. With such constructions, the ordinary lighting precedure is to first open the plug valve all the way, so as to purge the gas flow lines of any air which may have inadvertently leaked intosuch lines; second, to partly close the plug valve to a position where the valve port bleeders permit a very small flow of combustible gas and combustion-supporting gas ice hr suchproportions that the mixture is rich in combustible gas, and additionally in some cases to provide a very small flow'of blast gas;--third, tofignite the gas mixture, such as by means of a spark lighter; fourth, to turn the plug valve to the full open position so that the bleeder congases are increasing their flow, the blast gas flow is also gradually increased at such a rate proportional to the combustible gas mixture that the combustion is maintained and the flame not blown out by the blast gas.

Other types of valving arrangements have been used.

One such other arrangement, for instance, consisted of three separate tapered plug valves, one for'each gas,

with their motions synchronized by 'a set of intermeshing spur gears. Each of the tapered plug valves was provided with bleeder grooves so that the functionof the set of 1 three valves in controlling the flow of the three gases during the lighting operation was essentially the same as that hereinabove described with respect to, a single plug valve having three ports.

Some past gun constructions have comprised either needle valves or poppet valves, one for each gas with mechanical means interlocking the action of the valves and providing means for gradually opening such valves.

Here again the functional control of the flow of gases was such as to produce essentially the same relative flow of gases during the lighting cycle as hcreinabove described in connection with the example of the single'plug valve having multiple ports.

'All of these past constructions have proved quite satisj factory for the operation of manually lighted heat-fusible material spray guns where the conditions of use were such that lighting only had to be done occasionally. One of the objections to such previous constructions is that such guns do not lend themselves readily to automatic lighting.

Another objection to such constructions is that the lighting cycle is quite long and involved, so that it is impractical .Iwith' such guns to turn them off and light them frequently. This has been a serious handicap in the past, particularly for applications such as the metal spraying of articles passing in front of the guns on a conveyor. The diificulty of lighting and shutting oil. the guns has been suchv that for -most such applications it has been common practice to simply leave the guns lighted even when they were not spraying on to anything Methods have been developed for stopping the feed of metal (or other heat-fusible material) when no object is in front of the gun, but it has still remained common practice to allow the flame to continue with full gas consumption even when the gun is not spraying.

Another objection to such past gun constructions has been that considerable skill is required of the operator to properly and safely light and operate such equipment.

It is the object of this invention to provide valving control means for heat-fusible material spray guns which will permit ready and rapid lighting and shutting off of will permit reduction of the flow of gases to reduce the total cost of the spraying operation when spraying is to be done intermittently.

It isstill another object of this invention to provide Patented Jan. 15, 1963 3 valve control means for heat-fusible material spray guns which will permit lighting and shutting off of the gun without requiring special skill of the operator.

It is still another object of this invention to provide valve control means for heat-fusible material spray guns which will be readily adaptable to completely automatic operation, including automatic lighting.

It is still another object of this invention to provide a heat-fusible material spray gun having valve control means for complete automatic operation of such gun.

'It is a still further object of this invention to provide a heat-fusible material spray gun which will overcome the hereinabove stated objections to previous constructions.

These and other objectives of this invention will become evident from the following description read in conjunction with the drawings in which:

FIG. 1 is a diagrammatic side elevation, partially in section, showing an embodiment of a valving system in accordance with the invention, connected with a heatfusible material spray gun;

FIG. 2 is an enlarged vertical section of an embodiment of a valve for the valving system in accordance with the invention;

FIG. 3 is an enlarged vertical section of an embodiment of a further valve for the valving system in accordance with the invention;

FIG. 4 is an enlarged vertical section of an embodiment of a dual valve for the valving system in accordance with the invention;

FIG. 5 is a partial X-ray perspective view of a portion of the valve shown in FIG. 4;

FIG. 6 is a diagrammatic perspective view of a timing motor and switching arrangement for the valving system in accordance with the invention;

FIG. 7 diagrammatically shows an alternate embodiment of a valving arrangement for the valving system in accordance with the invention;

FIG. 8 diagrammatically shows still a further alternate embodiment of a valving arrangement for the valving system in accordance with the invention;

FIG. 9 is an enlarged vertical section of a further embodiment of a valving arrangement for the valving system in accordance with the invention;

FIG. 10 is an enlarged vertical section of a still further embodiment of a valve for the system in accordance with the invention;

FIG. 11 diagrammatically shows an electric ignition system for lighting the heat-fusible spray gun in accordance with the invention;

FIG. 12 diagrammatically shows an embodiment of the valving system, in accordance with the invention, connected with the heat-fusible material spray gun;

FIG. 13 is a diagram of the circuit for the operation of the valving system shown in FIG. 12; and

FIG. 14 diagrammatically shows a plan view of an arrangement for automatic spraying actuation in accordance with the invention.

In accordance with the invention a valving system is provided in combination with a heat-fusible material spray gun having gas conduit means for supplying at least one component of a combustible gas mixture to the gun. This valving system has first valve means with a first and second operating position connected in the conduit means, and second valve means with a first and second operating position connected in the conduit means. These valve means and their associated portions of the conduit means define in one sequential operational position for the first and second valve means, a full operational gas flow path through the conduit means, and in an alternate sequential operational position of the first and second valve means, a reduced gas flow path through said conduit means.

Where the gun is provided with separate gas conduit means for the combustible gas and for the combustionsupporting gas, a valving system, as described above, is preferably provided for each of the gas conduits. Additionally if the gun has a separate blast gas conduit, the valving system as described above is additionally provided for this conduit.

Referring to FIG. 1, 1 is a gas head of a conventional heat-fusible material spray gun. 2 is a heat-fusible material conduit through said gas head. 3 and 4 are combustion supporting and combustible gas conduits respectively, which lead from hose connection fittings 5 and 6, which connect through stems 7 and 8 to hoses 9 and 10. Hoses 9 and 10 serve as conduits for combustion supporting and combustible gas respectively, so that gases flowing through these hoses flow through hose stems 7 and 8, hose fittings 5 and 6, and gas head conduits 3 and 4. Conduit 11 connects with the termination of conduits 3 and 4 and leads to annular groove 12 at the nozzle seat of the gas head 13. Conduit 14 in gas head 1 connects between blast gas chamber 15 and hose fitting 16. Hose stem 17 connects to hose fitting 16 and also to hose 18. Blast gas flowing through hose 18 passes through hose stem 17, hose fitting 16, and conduit 14 into chamber 15.

Chamber 15 is partially defined by the configuration of gas head 1 and partially by blast gas cap 19. Gas nozzle 20 is attached to gas head seat 13 with a gas-tight seal and is fastened in place by nut 21. Nozzle 20 is provided with a central conduit 22, which connects up with conduit 2, so that heat-fusible material may be fed through conduit 2, through conduit 22, and out through the front end of nozzle 20 and blast gas cap 19. A multiple number of gaspassages 23 are provided in gas nozzle 20, leading from the seat of said nozzle to the tip thereof. Such passages surround the central conduit 22 and connect annular groove 12 with the outer tip of nozzle 20.

Valves 24 and 25 are schematically shown connected in series in hose conduit 9. Valves 26 and 27 are schematically shown connected in series in hose conduit 10. Valves 28 and 29 are schematically shown connected in series in hose conduit 18. Although valves 24, 25, 26, 27, 28 and 29 are only shown schematically in FIG. 1, they will be hereinafter more fully illustrated and described.

Said valves 24, 25, 26, 27, 28, and 29 are schematically represented as electrically operated solenoid valves, and each is provided with a pair of electrical wires shown as 30, 31, 32, 33, 34, and 35 respectively. These wires are connected up to actuating switches which are not shown in FIG. 1, but will be hereinafter more fully de' scribed and illustrated.

Hose conduits 9, 10, and 18 are connected to sources of combustion supporting gas, combustible gas, and blast gas respectively. Sources for these gases are not shown, since such sources are readily known in the art and may consist, for instance, of bottled gases released through pressure regulators to the hoses, or optionally, in the case of the blast gas, may consist of, for instance, an air com-- pressor provided with a regulating valve. It is under stood that these gas sources supply gases to hoses 9, 10, and 18 under regulated pressure.

Attached to gas head 1 is heat-fusible material feeding means 36. Details of said feeding means are not shown since many such satisfactory heat-fusible material feeding means are well known in the art which are capable of feeding heat-fusible material to the gas head conduit, either in the form of a continually fed rod or wire or in the form of a gas-borne stream of finely divided material.

In operation combustion supporting gas under regulated pressure enters hose 9 and passes in series through valves 24 and 25, through hose stem 7, hose fitting 5, conduit 3, and enters conduit 11. Combustible gas enters through hose 10 and passes in series through valves 27 and 26, through hose stem 8, hose fitting 6, conduit 4, and enters conduit 11, where it mixes with combustion supporting gas entering conduit 11 from conduit 3. The mixture of combustible gas and combustion supporting gas, which will hereinafter be referred to as combustible gas mixture, passes from conduit 11 through annular groove 12,

through the multiple passages 23, and emerges from the tip of gas head nozzle 20 to form a flame at said tip, said flame defining a heating zone for heat-fusible material. Said heat-fusible material in either rod form or as finely divided particles is fed by feeding means 36 through conduit 2, conduit 22, and from the tip of nozzle 20 into said heating zone.

In operation a blast gas, such as compressed air, enters from a pressure regulated source (not shown) into hose 18 and passes in series through valves 29 and 28, through hose stem 17, hose fitting 16, conduit 14, and emerges into chamber 15. The outer periphery of the flame end of nozzle 20 is somewhat tapered, and the inner surface of blast gas cap 19 adjacent said tapered end of said nozzle is also somewhat tapered on its inner surface. Nozzle 20 and blast gas cap 19 therefore describe a tapered annular passage for blast gas from chamber out through the end of blast gas cap 19. In operation the blast gas emerges from chamber 15 through the end of blast gas cap 19 to surround the flame and heating zone at the tip of nozzle 20. Said blast gas performs the function of imparting to the particles of at least partially heat-softened heat-fusible material a rela: tively high velocity, which carries them to a surface to be coated and causes them to impact upon such surface with a relatively high degree of impact. In the case where the heat-fusible material fed into the heating zone is in the form of a rod or wire, said blast gas additionally performs the function of contributing at least part of the energy for atomizing the heat-softened tip of such rod or wire to thereby form atomized or finely divided particles of such material.

All of the above description describes the usual construction of heat-fusible material spray guns as they are are well known in the art, except for the novel arrangement of valves for control of the gases used, and such arrangement and control will be hereinafter more fully described.

In place of the typical heat-fusible material spray gun shown, any other known or conventional heat-fusible material spray gun may be used as, for example, of the type which does not have a separate blast gas conduit but in which the expansion of the combustion gases, upon burning, is used for the blast gas effect.

Referring to FIG. 2, 24 is an electrically operated solenoid valve whichwas illustrated schematically as valve 24 in FIG. 1. This is a conventional valve well known in the art and consists of a valve body 37, with an inlet conduit 38, a tapered seat portion 39, and an outlet conduit 40. When the valve is open, gas may pass through conduit 38, seat portion 39, and through conduit 40. Valve stem 41 is made of a magnetic material, such as steel, and has a tapered lower end 42, which conforms to the contour of tapered seat portion 39. A conventional packing is provided at 43, which is tightened and secured by nut 44, so as to permit valve stem 41 to slide through said packing and yet prevent the escape of gas through said packing. A spring 45 is arranged to press downward against a pin 46 which extends through valve stem 41, so that said spring urges said stem downward toward a closed position of the valve. A housing '47 is rigidly mounted on valve body 37 and contains and supports electrical solenoid coil 48 which surrounds the upper end of valve stem 41. Solenoid coil 48 is provided with electrical wire connectors 30 which lead to switching means and power source (not shown). Cover 50 is rigidly fastened to housing 47 to close the housing and to provide resistance to the pressure of spring 45 at its upper end.

In operation when no current is supplied through leads 30, valve stem 41 is urged to its most downward operational position by spring 45, so that the valve is closed to the flow of gas by the contact of valve stem tapered portion 42 with tapered valve seat portion 39. When an electrical current of the proper voltage is supplied to solenoid coil 48 through electrical wires 30, a magnetic fieldis' developed in the coil of sufiicient strength to pull valve stem 41 upwards in opposition to the force of spring 45 and hence open the valve by separating the end'of valve stem 42 from seat portion 39. This valve 24 there fore has two operational positions, i.e., a fully open operational position and a closed operational position.

Referring to FIG. 3, 25 is a solenoid valve which was schematically represented as 25 in FIG. 1. This valve is almost identical in its construction and operation to valve 24, illustrated in FIG. 2. For convenience in referring to the structure, many of the elements which were numbered in FIG. 2 have been given similar numbers with the suifix a in FIG. 3. The only difference between the valve 24 and the valve 25 is that the valve 24 closes completely when the solenoid is not energized, whereas the valve 25 closes sufliciently to restrict the flow of gas therethrough but it does not close completely, and thus does not stop the flow of gas altogether. This result is obtained by proportioning the length of valve stem 41a from the position of pin 46a to the tapered point of said stem 42a, such that the tapered pin 46a strikes the top of nut 44a before tapered end 42a contacts tapered seat portion 39a. In operation when the solenoid 48a is not energized, the valve is at one of its operational positions partly closed, due to the urging by spring 45a of valve stem 41a to the position where pin 46:: contacts nut 44a. In this position the tapered portion 42:: and seat portion 39a are sufliciently close so as to form a metering orifice which restricts the flow of gas through the valve to a predetermined relatively small amount. -When the solenoid coil 48 is energized the valve is actuated 'to its other opera tional position, i.-e.,' its fully open position, with thevalve stem forced upwardly by the electric magnetic force.

Referring to FIGS.'1, 2, and 3, in operation, combustion supporting gas is fed under regulated pressure, as previously described, to hose 9. Under normal starting conditions, both valves 24 and 25 are unenergized. There fore valve 24 is closed to'complete shut-off position, and valve 25 is closed to its metering position, but not to complete shut-off. Since valve 24 is closed no gas flows, In operation, first both valves 24 and 25 are energized to provide full flow of gas for the purging step; second, valve 25 closes to its metering position to provide a relatively small flow of gas suitable for lighting purposes. At this stage (assuming that the combustible gas is also flowing sufficiently for lighting purposes), the flame is ignited by a spark lighter, pilot light, electricalspark, or other means (not shown); third, valve 25 is energized so that it opens to the full open position, and since valve 24 is also energized to the full open position, full flow of gas isprovided for the normal spraying operation.

Referring to FIG. 1, valves 26 and 27 are structurally and functionally identical to valves 24 and 25 illustrated more particularly in FIGS. 2 and 3, with the'exception that the length of thevalve stem 41a from the pin 46a to the point 42a is individually proportioned in valve 27 to meter the predetermined desirable flow of combustiblegasrequired for the lighting condition.

Referring to FIG. 1, valves 28 and 29 are identical to valves 24 and 25, more particularly illustrated in FIGS;

2 and 3, with the exception that the length of the valve stem 41a from the pin 46a to its point 42a is proportioned so as to meter out the proper amount of blast gas required for the lighting operation. It should be notedthat while the blast gas is not necessarily involved in the combustion that forms the flame, nevertheless it is usually desirable to have a very small flow of blast gas during the lighting condition to prevent the possibility of a combustible gas mixture collecting in the chamber 15 which might lead to the possibility of an explosion upon ignition. In operation all of the valves are actuated in proper sequence by energizing them with an electrical current through their respective electrical connections by means of a switching mechanism which will hereinafter be more fully described. In the first purging step, all six valves,'

Nos. 24, 25, 26, 27, 28, and 29, are energized and fully opened. In the lighting step valves 24, 26 and 28 remain wide open, whereas valves 25, 27 and 29 close to their metering positions to provide the proper restricted flow of each gas suitable for lighting. During the operating step, valves 24, 26, and 28 remain energized and fully opened, and valves 25, 27 and 29 are energized and caused to open fully, thus permitting full flow of all three gases as required by the normal operation of spraying.

The valve pairs 24, 26, 27; and 28, 29 or each of these pairs may be combined in a single housing forming in effect a unitary valve structure which is the functional equivalent of the two valves. As shown in FIGS. 4 and 5, a symmetrical valve body 37b is positioned in the gas conduit 38b40b. The valve body has a central cylindrical bore 92 which extends therethrough coaxially in the axial direction of the conduit. The body 37b also has a transverse cylindrical bore through which the valve stem 41b of magnetic material, slides. A gas-tight seal is formed with the valve stem 41b by means of the O-rings 93. Two diametrically opposed housings 47b are connected to opposite sides of the body 37b coaxially with the stem 41b. Each of these housings is provided with a cover 50b, a spring 45b acting on the valve stem 41b, and a solenoid coil 48b provided with electrical leads 31b. Each of the springs 45b presses at one end against the cover 50b and at the other end against the pin 46b extending through the valve stem 41b. The valve stem 41b, as may thus be seen in FIG. 5, is provided with an imperforate or solid portion in its center and has on one side the small orifice 94 and on the opposite side the larger orifice 95. In place of the orifice 94 a small annular groove (not shown) may be cut in the stern 41b and in place of the orifice 95 a larger annular groove (not shown) may be cut in the stem 41b.

When neither of the solenoids 48b are energized the forces of the opposed springs 45b equalize each other so that the valve stem 41b is maintained in the position shown in FIG. 4 of the drawing, and since the solid central portion obstructs the bore 92, the valve is, in effect, in its closed position. When the lower solenoid 48b is energized the valve stem 41b will be pulled downwardly so that the smaller hole or orifice 94 will align with the bore 92, so that a reduced gas flow through conduit 38b and 40b occurs. Conversely, when the upper solenoid 48b is energized, the valve stem 41b is pulled upwardly, compressing the upper spring 45b and the larger orifice 95 is aligned with the bore 92, so that full gas flow through the conduit may be effected. Thus, when neither of the solenoids are energized, the valve is maintained in its shut position. When the lower solenoid is energized, a reduced gas flow occurs corresponding to an opening of the valve 24 while the valve 25 is not energized and thus closed to a partial flow position, and energization of the upper solenoid 48b corresponds to an operational position when both the valves 24 and 25 are energized to their open position.

In operation for lighting first the upper solenoid 48b is energized, aligning the orifice 95 with the bore 92 and allowing full gas flow for purging. Thereafter the upper solenoid 48b is de-energized and the lower solenoid 48b energized, forcing the valve stem 41b downwardly, aligning the orifice 94 with the bore 92, providing reduced gas flow for lighting. After the lighting operation the upper solenoid 48b is energized and the lower solenoid deenergized, again moving valve stem 41b to align the orifice 95 with the bore 92 for full flow and spraying operation. The valve should be positioned sufficiently far from the gun and the valve stem 41b should operate sufiiciently rapidly to eliminate the shutotf effect on transfer from the orifice 94 to 95 and vice-versa, and thus prevent a flame out.

Referring to FIG. 6, 51 represents a timer motor means which is not shown in detail since such timer motors are well known in the art. Timer motor 51 is connected by wire 52 to power source 53 and thence by wire 54 to push button switch 55 which can make contact with conductor 56 which connects with wire 57 leading to timer motor. Timer motor shaft 58 carries switch actuating earns 59, 60, 61, 62, 63 and 64. Cams 59, 60, and 61 have a single rise so that in one revolution of said cams, their associated switches may be opened once and closed once. Cams 62, 63 and 64 have two rises so that their associated switches can be opened and closed twice during a revolution. Switch means 65, 66, 67, 68, 69, and 70 ride respectively as cam followers on cams 59, 60, 61, 62, 63, and 64. Switch contacts 71, 72, 73, 74, 75, and 76 are the contact points for the switch elements 65, 66, 67, 68, 69 and 70 respectively. Switch contacts 71, 72, 73, 74, 75 and 76 are connected with conductors 77, 78, 79, 80, 81 and 82 respectively. Conductors 77, 78, 79, 80, 81, and 82 are connected to power sources 83, 84, 85, 86, 87, and 88 respectively. Power sources 83, 84, 85, 86, 87, and 88 are connected to conducting wires 30, 32, 34, 31, 33, and 35 respectively. Switch elements 65, 66, 67, 68, 69, and 70 are also connected to conducting wires 30, 32, 34, 31, 33, and 35 respectively. Said conducting wires 30, 32, 34, 31, 33, and 35 are connected to solenoid valves as illustrated in FIGS. 1, 2 and 3, and as previously described.

In operation push button switch 55 is closed, thereby starting timer motor 51, causing cams 59, 60, 61, 62, 63, and 64 to rotate. Due to such rotation, the first purging stage of the operation of the spraying equipment will be obtained when the cams rotate to first close and make electrical contact with all of the switch elements 71, 72, 73, 74, 75, and 76. When this occurs all of the solenoid valves 24, 26, 28, 25, 27, and 29 respectively are open (position shown in FIGS. 2 and 3). As the timer motor cam shaft continues to rotate, earns 59, 60, and 61 permit contact points 71, 72, and 73 to remain in contact with their respective switch elements, and hence valves 24, 26, and 28 remain open. During this continued rotation, however, cams 62, 63, and 64 cause opening of switch elements 68, 69, and 70 so as to bring them out of contact with contact points 74, 75, and 76 respectively. Hence valves 25, 27, and 29 will close to their metering positions suitable for lighting.

By further rotation of timer cam shaft 58, contact will again be made with contact elements 74, 75, and 76, while contact elements 71, 72, and 73 remain in contact. As a consequence, all valves 24, 26, 28, 25, 27, and 29 will be open and hence in suitable position for normal operation. If at this point push button switch 25 is opened, cam shaft 58 will cease rotating, and the gases will continue to fiow under full operating conditions.

if it is desired to shut off the flow of gases and stop the guns operation, push button switch 55 may again be closed, causing cam shaft 58 to rotate further until it reaches the position where all switch elements 65, 66, 67, 68, 69, and 70 are taken out of contact with contact points 71, 72, 73, 74, 75, and 76 respectively. This will cause all of the valves 24, 26, and 28 to close completely, hence shutting olf all flow of gases, and also to cause valves 25, 27, and 29 to return to their metering positions ready for restarting the lighting cycle. If desired, an additional cam can be provided on cam shaft 58 with a switch connected into push button circuit of timer motor 51 in a manner well known in the art, so that it is only necessary for the operator to push push button 55 for a short period of time to start the operation of the cycle. Thereafter this additional cam and switch operate the timer motor in lieu of the push button through the cycle to the full operating position and then such cam and switch arrangement may disconnect the timer motor so as to leave the flow of gases in the full operating condition. In such case a sec- 0nd actuation of the push button will restart the motor so as to continue the final rotation of cam shaft 58 for stopping the flow of gases when shut down is desired.

As an alternative embodiment of this invention, additional switches can be connected into the circuits of wires 31, 33, and 35, such as is shown at 89, 90, and 91, so that by the opening of said switches, valves 25, 27, and 29 are closed to their metering positions independently from the operation of the timer motor. This action may be desirable, for instance, to produce an idle flame condition. It is obvious that since the gases have not been turned off in this situation, but only reduced in their flow to the lighting condition, that the flame will not go out altogether but remain as an idle flame which will resume its normal operating size when valves 25, 27, and 29 are reopened to their full open position.

In operation, for instance, when spraying articles moving in sequence in front of the apparatus for applying heat-fusible material coatings, any desired interconnection can be made between the conveyor carrying the articles to be sprayed and the switches 89, 90, and 91, so that when no article is in spraying position, such switches can be opened, and the flame reduced to idle condition. It is obvious that large savings in gas costs will result from this arrangement. As already mentioned, it is already well known in the art that the heat-fusible material feeding means 36 can also be connected up by some actuating means related to the conveyor or articles being passed in front of the spraying apparatus, so as to also stop the feeding of heat-fusible material when no object is in front of the spraying apparatus.

An alternative construction for the valve arrangement is shown in FIG. 7, in .which valves 24b and 25b are shown in parallel arrangement, rather than in series arrangement. In this case incoming gas conduit 9b splits into two branches, 1001) and 101b, leading respectively to valves 24b and 25b which are schematically shown in FIG. 5. Both valves 24b and 25b in this case are identical to the valve 24 shown and described in connection with FIG. 2. Both of these Valves have two operational positions, e.g., ful-l open and full closed. Valve 24b connects to conduit 102b, in which is located metering orifice 10312. Valve 25b is connected to conduit 104b, in which may be located a large metering orifice 105b and thence connects back through a Y connection at the discharge of orifice 10317 and forms conduit 9b.

Metering orifice 1031) or its equivalent is required to' provide the restricted flow necessary for the lighting and/ or idle flame condition. Metering orifice 105b may be optionally added, if desired, to provide additional steps in the control of thefiow of the gas.

In operation valves 24b and 25b are open for the purge cycle; valve 25b is closed for the lighting step. With valve 25b closed and valve 2412 open, a small flow is provided as allowed by the metering orifice 1-03b. Full flow for normal operation is provided when valve 25b is again opened, so that both valves 24b and 25b are wide open.

Sometimes it is desirable to provide more'steps from the lighting position to the full open position and the arrangement shown in FIG. 7 permits this. In such case the lowest flow step is provided with valve 25b being closed and 24b being open, orifice 103b providing the restriction to give this lowest flow. Second stage of flow is provided by closing valve 24b and opening valve 25b, at which time larger'orifice 1-0517 meters a larger flow. The third stage is provided when both valves 24b and 25b are opened so that the total maximum flow is obtained as the combined flow through both orifices 103b and 10511.

It must be clearly understood that the metering effects of orifices 10312 and 105b can be obtained in many well known ways besides the use of orifices, such as for instance dimensioning the pipe or conduit sizes so as to properly restrict the fiow. Alternatively, valves which only partially open when in the open position, can be provided for valves 24b and 25b. It is obvious that the proper proportioning of the partially open valve can provide equivalent restrictions to those provided by orifices 10% and 1051) in the illustration of FIG. 7. It is also possible to make the orifices 103b and 1051: adjust in their place. The degree the valve is manually adjusted to will thus determine the size of the orifice and will allow a pre-adjustment to the optimum orifice size for any operational conditions.

It should be clearly understood that either the series valve arrangement previously described in connection with FIG. 1 or the parallel arrangement described in connection with FIG. 7 may be used, either in all of the various gas lines required or these systems may be used alternately in these various gas lines.

It is also obvious that more than two valves may be used to provide more steps in the control of the flow, whether the series arrangement illustrated in FIG. 1

' or the parallel arrangement illustrated in FIG. 7 is used.

FIG. 8 represents an alternative embodiment of this invention, in which three valves are shown in parallel arrangement, the valves being shown schematically as 201, 202, and 203, each of said valves being identical in construction to that shown in connection with valve 24 of FIG. 2. In this case conduit splits into three parallel conduits 204, 205, and 206, connecting respectively with valves 201, 202, and 203, which in turn connect with conduits 207, 208, and 209 respectively. In conduits 207, 208 and 209 are orifice restrictions 210, 211, and 212 respectively. Beyond said orifices, conduits 207, 208, and 209 converge into a single outgoing'conduit 9c. As the orifices 210, 211, and 212 are proportioned differently, it is obvious that seven different flow rates may be obtained. These are obtained as follows: The first flow rate is obtained when only valve 201 is open and flow is restricted by orifice 210. The second flow rate is obtained when valves 201 and 202 are open and flow rate is restricted by orifices 210 and 211 in parallel. The third flow rate is obtained when valves 201, 202, and 203 are open and flow rate is restricted by orifices 210, 211, and 212 in parallel. The fourth flow rate is obtained when valve 202 is open and flow rate is restricted by orifice 211. The fifth flow rate is obtained when valves 202 and'203 are open and flow is restricted by orifices 211 and 212 in parallel. The sixth flow rate is obtained when valve 203 is open and orifice 212 restricts the flow.

It should be obvious to anyone skilled in the art that other means, such as pneumatic, hydraulic, or mechanical, may be used besides electromagnetic means for actuating the valve plungers between their open and close positions.

One such arrangement for operating a valve pneumatically is illustrated in FIG. 9 where valve 24d is somewhat similar to valve 24 illustrated in FIG. 2, except that it is hydraulically or pneumatically operated instead of electrically. In this case valve body 37d is provided with inlet onduit 38a, seat portion 39d, outlet conduit 40d, valve stem 41d, with pointed end 42d,

which slides through packing 43d, which is held by nut 44d. In this case pneumatic or hydraulic cylinder 301 is mounted on valve body 37d and is provided with an inlet for pneumatic or hydraulic fluid 302. Valve stem 41d is provided with piston 303, around the periphery of which is the O-ring seal 304 of resilient material. In this case spring 305 presses against nut 44d and upward against pin 46:! through stem 41d, so as to urge valve stem 41d upwards to the open position. In this case the valve is closed when pneumatic or hydraulic fluid is introduced under pressure through inlet 302, so

as to oppose the action of spring 305 and close the valve. It is obvious that if this type of valve is used, pneumatic or hydraulic fluid under pressure is utilized as an actuating fluid through proper piping or conduit means and by means of suitable valving means for turning on and turning off the flow of such fluid. In such 1 1 case the switches illustrated in FIG. 6 would be supplanted by fluid valves.

An example of a valve of the type suitable for use in connection with this invention, which is actuated mechanically, is shown in FIG. 10. 24a is a valve somewhat similar to valve 24 in connection with FIG. 2. Valve body 37e is provided with inlet conduit 38e, seat portion 39c, and outlet conduit 40c. Valve stem 41e is provided with pointed end 42c and slides through packing 43e, secured by nut 44a. Pin 46e extends through valve stem 41e so that spring 401 can press upward against said pin and downward against nut 44c, so as to urge valve stem 41c upward toward the open position. A sliding cylindrical cap 402 is provided, which will slide up and down on the end of valve stem 41c. Cap 402 is urged upwardly with respect to stem 41.2 by spring 403 which presses between said cap and pin 46e. Cap 402 is provided with a cross pin 404 upon which is mounted a roller 405. Said roller forms a cam follower for cam 406 mounted on cam shaft 58e. In operation cam 406 is pressed by cam follower 405, which is urged upwardly with cap 402 by spring 403 and spring 401. Spring 403 is made stiffer than spring 401. When cam shaft 58e rotates until the cam rise reaches the roller 405, the cam rise forces roller 405 and cap 402 downward. Since spring 403 is stiffer than spring 401, valve stem 41a is forced downward until it closes. After closing, slight further urging downward by cam r-ise simply causes compression of spring 403. If desired, this valve could be proportioned so as not to close completely, but so as to provide a metering orifice between valve stem 422 and valve seat portion 39e, similar to that described in connection with valve '25 illustrated in FIG. 3.

A set of valves constructed as described in connection with valve 24c illustrated in FIG. may be actuated in proper sequence by a cam shaft which is either operated manually or by a timer motor, such as was illustrated in connection with FIG. 6. In such case the various cams on cam shaft 58e would correspond to the various cams shown on cam shaft 58, except that their rises and falls would be reversed, since the valve 24e was shown to close with the rise of the cam.

It is also obvious that electrical means other than solenoid valves may be used to actuate the gas flow valves, such as by torque motors and other devices well known in the art.

As previously mentioned, it may be desirable to add an additional cam to cam shaft 58e. Referring to FIG. 11, such an extension of cam shaft 58 is indicated as 58]. On the end of the cam shaft has been added a cam 501. Said cam is arranged to actuate switch element 502, so as to make or break contact with contact point 503. Contact point 503 is connected by means of connecting wire 504 to a source of alternating current schematically indicated at 505, which in turn is connected to the primary of a high tension transformer schematically indicated at 506. Switch element 502 is connected through conducting wire 507 to the other lead of the primary of said transformer 506. The high voltage secondary of transformer 506 is connected to a spark gap illustrated schematically at 508. Said spark gap may be located adjacent the gas nozzle outside of the gas blast cap 19 illustrated in FIG. 1. The fall of the cam 501 would be so located on cam shaft 58f that when the other cams set the valves for the lighting position, the fall of the cam would cause switch element 502 to make connection with contact point 503 and hence cause an electrical spark at 508 adjacent the nozzle, hence causing ignition.

One of the primary advantages of this stepped valve control system is the ease with which this method of control may be automated for partial or complete automatic operation of heat-fusible spraying apparatuses.

FIG. 12 diagrammatically shows a complete valving system arrangement in accordance with the invention, connected to a heat-fusible material spray gun designated 96. The blast gas for the heat-fusible material spray gun is air, and a source of compressed air, such as a compressor, compressed air tank, or the like, is connected to the connection 601a. Connected immediately past connection 601a is a pressure-actuated switch 602a which will close at a pressure of 60 lbs. per square inch or greater. Connected in series past the switch 602a is the electrically operated valve 603a which will open when electrically energized, the pressure indicating gauge 604, the oil and moisture trap 606, the pressure regulating valve 605a, the pressure indicating gauge 607a, the oil and moisture trap 606, the variable area flow meter 608a and three parallelly connected lines containing the manually adjustable needle valves 611a and 610a and the solenoid valves 701a, 702a and 703a corresponding in structure to the valve 24 of FIG. 2. The line 609a connects the branch lines with the heat-fusible material spray gun 96.

The combustible gas is acetylene and is supplied by a source, such as a pressure bottle, to the acetylene line through the connection 601b. The acetylene line has connected, in series, the pressure actuated switch 60211 which closes at a pressure of 10 lbs. per square inch or greater; the electrically operated solenoid valve 603b which opens when electrically energized; the pressure gauge 604; pressure regulator 605b; the pressure gauge 607b; the variable area flow meter 608b, and the two parallel lines containing manually operated needle valves 61% and 611b and the solenoid operated valves 724k and 725b corresponding to the valve 24 in structure. The two parallel branch lines then join to the line 60% leading to the mctallizing gun.

The combustion supporting gas is oxygen and is supplied from a suitable source as, for example, from an oxygen bottle or the like, to the oxygen line through the connection 601a. Connected in series to the oxygen line is the electrically operated valve 603c which opens when energized; the pressure gauge 604; pressure regulator 605a; the pressure gauge 607a; the variable area flow meter 608s and the two parallelly branched lines containing the solenoid operated valves 724a and 725a corresponding in structure to the valve 24 and the manually adjustable needle valves 610a and 6110. The two parallel branched lines join together at the line 6090 which leads to the heat-fusible material spray gun 96.

FIG. 13 is a wiring diagram of an automatic control system for the valve arrangement shown in FIG. 12. In this circuit diagram 801a is connected to the ungrounded side of a source of volts, 60 cycles, single phase, electrical power; and 801b is connected to the grounded side (if any) of said source; 8010 and 801d are connected to a switch (not shown) which is closed when the ventilating system for the mctallizing area is in operation; 801a and 801i are connections for a remote idle switch (not shown) arranged to be closed automatically or otherwise when it is wished to cause the mctallizing gun to stop spraying but without extinguishing the flame; 802 is a power supply and speed control unit of conventional construction for the mctallizing gun 96, of which thermal relay 8021:, relay 802r and momentary contact switch 802b are some of the components; 803 is a multiconductor cable which connects the motor on the metallizing gun to its power supply 802; 804 is a high voltage ignition transformer used to produce the gas lighting spark on a conventional mctallizing gun; 804a are the electrical conductors between the ignition device on said mctallizing gun and ignition transformer 804; 805a, 805b, 8050, 805d, 805e, SQSf, are fuses of appro riate capacity; 806 is an electric motor-powered ventilator connected by means of two wires 806d; 807a is the single pole, single throw, normally open pressure switch which is closed when compressed air is available, as shown in FIG. 12 as 602a; 807b is the single pole, single throw, normally open pressure-operated switch arranged to close when fuel gas is available as shown in FIG. 12 as 602b; 8070 is a pilot light associated with switch 807b; 807d is a pilot light associated with switch 807a; 8070 is the electrical operator for the air valve shown as 603a in FIG. 12; 807 is the electrical operator for the oxygen valve shown as 6030 in FIG. 12; 807g is the electrical operator for the valve shown as 6031) in FIG. 12; 808a, 808b and 8080 are the electrical operators for the valves 703a, 725b and 7250 shown in FIG. 12; 808d is the electrical operator for the valve shown as 702a in FIG. 12; 8080, 808] and 808g are the electrical operators for the valves shown in FIG. 12 numbered 701a, 724b and 7240 respectively; 809p is a relay having two normallly open poles 809p1 and 809p2; 810m is a relay having four poles, 810ml which is double throw, 810m2 which is normally open single throw, 810m3 which is normally open, single throw, and 810m4 which is single throw normally open; 811 is a two pole relay having one single throw normally open contact 811a and one single throw normally closed contact 811b; 812 is a slow-to-operate time delay relay having a single pole normally closed contact 812a; 813 is the motor of a program timer having six cam-operated switches; 813t1, 813t2, 813t3, 81314, 813t5, and 81316, corresponding for example to FIG. 6.

814a and- 814b are single pole momentary contact switches normally closed and open respectively; 815 is a single pole normally open momentary contact switch; 816 is a single pole normally closed momentary contact switch; 817a is the normally open pole of a two-pole maintained contact switch; 817b is the normally closed pole of the same two-pole maintained contact switch; poles 817a and 817b operate simultaneously; 818 is a single pole normally open momentary contact switch; 819 is a three-pole momentary contact switch having one normally closed pole 819a and two normally open poles 81% and 8190; 820a is a pilot light connected across the operating coil of relay 809p; 82% is a pilot light connected to show when thermal relay 82011 is closed; 8200 is a pilot light connected across the coil of relay 810m; 820d is a pilot light connected across thec oil of relay 812; 820a is a pilot light connected to indicate when switch 819 is operated. In operation the air, acetylene and oxygen lines are connected to suitable gas sources as, for example, air at 100 lbs. per square inch, acetylene at 15 lbs. per square inch, and oxygen at 50 lbs per square inch.

The switch at 8010 and 801a is closed as, for example, by means of a relay which is actuated when the ventilating equipment for the metallizing space is operating. The heat-fusible material gun, i.e. the gun 96, is loaded with conventional heat-fusible material for spraying as, for example, is threaded with a metallizing wire and its electric motor is connected by means of the cable 803 to the power supply and speed control 802. The high tension leads 804a are connected to the spark igniter as, for example, the spark plug 508 tof the metallizing gun, as shown in FIG. 11. With the ventilating equipment for the metallizing space operating and the switch at 8010 and 801d closed, the fuses 805a, 805b and 8050 are energized. The fuse 805a energizes the normally open contacts 809p1 and 809p2 of the relay 809p and one contact of the switch 815. Fuse 805b energizes the line side of the pressure switch 807b and if there is a supply of acetylene at suitable pressure, the switch 807b will close, causing the pilot light 8070. to light and ventilating blower 806 to run. The ventilating blower 806 will continue to run and provide ventilation for the equipment at all times that there is acetylene under pressure. The equipment is actuated and the power turned on by pressing the push button 815. This causes the relay 809p to close and since the relay contact 809 22 closes, the switch 815 is short-circuited so that the relay 809p will remain closed as long as power is supplied to connections 801a and 801b andthe ventilating interlock switch at 8010- 14' 801d is closed. The power may be shut off by pressing the switch 816, which again causes the relay 809p to open. Upon turning on the power in this manner with the closing of the relay contact 809p1 the switch 807a is energized through the fuse 805 If there is sufficient air pressure, the switch 807a will close, lighting the pilot light 807d and energizing the valve operators 807a, 807 and 807g. Closing of relay contact 809p1 also energizes fuse 805d, through which power is supplied to the motor power supply and speed control unit 802 and starts heating the thermal time delay relay 802k.

Closing of the pressure switch 8070 causes line voltage to be supplied to the push button switch 81412 through the timer contact 813t4 to normally open relay contact 810m2; to normally open relay contact 810m3 through normally closed momentary contact push button switch 814a, and to relay contact 810ml. Since the return from the relay 810m is through the thermal time delay relay 802k no further action can take place until this relay is heated up and closed. After a time delay sufii-- cient for operation of the time delay relay which has been determined as sufiicient to allow proper warm-up of the motor power supply and speed control unit 802, the time delay relay 802h closes, making operation of the relay 810m possible by manual operation of normally open momentary contact push button 814b.

If the air, acetylene and oxygen pressures have not been adjusted, this adjustment'may be elfected by operating the momentary contact switch 819 which energizes the valve coils 808a, 808b, 8080,808d, 808e, 8087, and 808g, causing the valves 703a, 725b, 7250, 702a, 701a; 724b and 7240 to open, thus allowing the full flow of .oxy gen, acetylene and air to the gun. While the switch 819 is held depressed and the valves themselves maintained open, the flow of air is adjusted by means of the regulator 605a, the How of acetylene by means of the regulator 605b and the flow of oxygen by means of the regulator 6050. The correct flow values are obtained bymeans of the meters 608, 608b and 6080 respectively. After these adjustments have been made the switch 819 is released and the valves will all automatically close. In order to test the spark for ignition the switch 818 may be closed, which energizes the ignition transformer and provides spark voltage to the metaillizing gun over the leads 804a.

With the wire threaded in the metallizing gun the electric drive of the gunmay be checked by depressing the contact switch 80212 which will cause the gun motor to run as long as the switch is depressed, provided of course, that the thermal time delay relay is previously closed.

After these previous checks the metallizing gun' is ready for lighting, which is effected by closing the switch 81412. This causes the relay 810m to operate and the pilot light 8200 to light. The relay 810m will be held closed even after the switch 814b is released, since when the relay 810m opzrates, contact 810m3 closes and con-v nects line voltage to relay coil 810m through the normally closed switch 814a. Simultaneously the contact 810ml transfers to supply operating voltage through the timer contact 81326 to the timer motor 813, which commences to run. At the same time power is supplied through the normally closed contacts 819a of the switch 819 to the valve operators 808e, 8087, and 808g and through timer contact 81373 to the valve operator 808d and through the relay contact 812a and timer contact 813t1 to the valve operators 808a, 8081) and 8080. This causes all the valves down stream of the flow meters to open and the full How of compressed air, acetylene and oxygen takes place for the purpose of purging any combustible mixture which may have accumulated in the hose line or metallizing gun parts. After approximately one second, timer contact 81324 transfers. timer contact 813t6 keeps power on timer motor 813 so that it may complete its cycle regardless of the operation of the other controls.

This through At the end of approximately 2 /2 seconds, timer contact 81311 opens, de-energizing valve coils 808a, 808b and 808c, and thus allowing valves 703a, 7251) and 725c to close. Almost immediately after, timer contact 81313 opens, de-energizing coil 808d and permitting valve 702a to close. At this point, by means of needle valves 610a, 61% and 610s it is possible to adjust the flow of air, acetylene and oxygen to the proper values of lighting the metallizing gun. This adjustment is made originally with the timer switches in this position but with the timer motor de-energized so that this adjustment may be made 2; lgisure. Once made this adjustment usually remains The lighting flow adjustment having been made, the timer proceeds to run approximately four seconds at which time timer switch 813t2 closes. This energizes ignition transformer 804, which by means of leads 804a causes a spark at the ignition plug on the metallizing gun, thus causing the combustible mixture of acetylene, oxygen andair to ignite and burn at the flow rates previously established for lighting flow. At the end of approximately five seconds, timer switch 813t2 opens, cutting off the ignition spark.

At the end of about 6 /2 seconds timer switches 813t1 and 813t3 again close, energizing valve coils 808a, 808b, 808e, 808d, and thus opening valves 703a, 725b, 725c and 702a, permitting full fiow of combustible gas and atomizing air to the metallizing gun.

After approximately seven seconds, timer switch 813t5 closes. Operating through relay contact 810m4 which is now closed, relay contact 81112 which is now closed and momentary contact switch 817!) which is now closed, relay 802r closes and the electric motor on the metallizing gun starts to run, feeding metallizing wire to the gas head of the metallizing gun, where it is melted, atomized and sprayed in typical metallizing gun fashion.

If it is desired to cause the metallizing gun to stop spraying, but without complete extinguishment of the flame, i.e. to place the gun in an idle condition, the switch 817a is closed. Normally closed switch 817b connected to switch 817a opens simultaneously, causing relay 8021' to open and the electric motor on the metallizing gun to stop. Simultaneously the closing of switch 817a energizes the time delay relay S12 and after a period of approximately 2 seconds the relay contact 312a opens and the valve coils 808a, 80812, and 8080 are de-energized, thus closing the valves 703a, 725b and 7250. Under these conditions the wire feed has stopped and the burner flame is very much reduced. Furthermore, cooling air in the proper amount,

as controlled by needle valve 611a through electric valve 702 which has remained open, is supplied to the gas head.

When it is desired to resume spraying, it is merely necessary to unlatch switch 817, permitting the contact 817:: to open, de-energizing relay 812 which permits contact 812a to close and re-establishes the and combustible gases to the metallizing gun. At the same time the contact 8171; has closed, which in turn closes the relay SilZr, thus starting the motor on the metallizing gun feeding the wire in the normal fashion for spraying.

The idling operation may be effected automatically by means of the relay 811 which, for example, may be actuated automatically when there is no workpiece to be sprayed within the spraying area of the metallizing gun. Thus, for example, workpieces to be sprayed may be conveyed in front of the metallizing gun and the relay 811 (lo-energized when the pieces pass within the spraying area of the gun and energized when the same pass out of the spraying area of the gun.

Referring to FIG. 14 automatic endless conveyor belt 143 of conventional construction is provided, which conveys the workpiece 144 past the metallizing gun 96. A photoelectric cell 141 is positioned adjacent the gun and a light beam projector 142 is positioned on the opposite side of the belt so that a beam of light therefrom is profull flow of air jected into the photo-electric cell. This beam of light will excite the photo-electric cell which is connected to relay S11 and which will actuate the same. As soon as the workpiece 144 is moved across the beam of light by means of the conveyor belt and thus in the spray area, the photoelectric cell is de-energized, as is the relay 811, and the metallizing gun 96 immediately automatically switches from idle to operational condition, effecting the spraying. As soon as the workpiece has passed the gun, the same will no longer interrupt the beam of light from the projector 142;, so that the same will strike the photo-electric cell 141, energizing the relay 811 and automatically causing the gun to go to its idle position in the manner described above.

If it is desired to completely shut off the metallizing gun but leave the main supply of air, acetylene and oxygen connected, and the motor power supply and speed control warmed up and ready to operate, it is merely necessary to press the switch 814a, thus opening the holding circuit through the relay contact 8101113 to the relay 810m. When the relay 810m is thus de-energized, the contact 810ml again transfers in such a manner that the voltage is fed to the closed cam switch 813-6, causing the timer to recycle to zero. Simultaneously with the de-energizing of the relay 810m relay contacts 819m2 open, de-energizing valve coils 808a through 808g and thus shutting otf all the air flow, acetylene flow and oxygen flow to the metallizing gun. Simultaneously the relay contact 8101214 opens which in turn causes relay 802r to open and the electric motor of the metallizing gun is stopped.

If during the normal operation of the gun the ventilat-.

ing system for the metallizing space should fail, the switch at 8010-4801:! will open, thus shutting off all the valves and stopping the wire feed as a safety feature.

Furthermore, if the compressed air supply should fail or its pressure fall below the desired value, pressure switch 807 will open, thus de-energizing the valve coils 807e, 807 and 897g, as well as the valve coils 808a through 808g and the relay 810m, thus causing an immediate shutdown preventing any possibility of accidental operation of the metallizing gun burner without air.

In addition to the above mentioned safety features it is possible to connect a photo-electric or thermally operated relay in series with the relay 810m in such a manner that if the metallizing gun flame is extinguished for any reason, the relay 810m will be de-energized and thus shut the system down.

It may thus be seen that with all the equipment and supplies in proper working order, it is only necessary to 8141) to start the equipment and the press the switch the equipment, all other operat1ons switch 814a to stop being automatic.

While the invention has been described in detail with reference to certain specific embodiments, various changes and modifications which fall within the spirit of the invention and scope of the appended claimswill become apparent to a skilled artisan.

We claim:

1. In a spraying system for spraying heat-fusible material including a heat-fusible material spray gun; gas conduit means for suplying at least one component of a combustible gas mixture to said gun, and valve means for controlling the flow of gas through said gas conduit means, the improvement which comprises said valve means being composed of first valve means having a first and second operating position connected in said conduit means, second valve means having a first and second position of operation connected in said conduit means, said valve means and their associated portions of said conduit means defining in one sequential operational position of said first and second valve means, a full operational gas flow path through said conduit means, and in an alternate sequential operational position of said first and second valve means, a reduced gas flow path through said conduit means and in a further alternate sequential operational position shutting off the gas flow through said conduit means, and means for actuating said valve means between their first and second operating positions to establish said one sequential operational position, said alternate sequential operational position and said still further alternate sequential operational position.

2. Improvement according to claim 1 in which said heat-fusible material spray gun has separate gas conduit means for combustible gas and a combustion supporting gas, and in which said first and second valve means are positioned in at least one of said gas conduit means.

3. Improvement according to claim 2, including first and second valve means in each of said conduit means.

4. Improvement according to claim 3, including blast gas conduit means additionally having first and second valve means connected therein.

5. Improvement according to claim 1, including blast gas conduit means additionally having first and second valve means connected therein.

. Improvement according to claim 1, including third valve means having a first and second position of operation connected in said conduit means, said valve means and their associated portions of said conduit means defining in one sequential operational position of said first, second and third valve means, a full operational gas flow path through said conduit means in an alternate sequential operational position of said first, second and third valve means, a reduced gas flow path through said conduit means, and in a further alternate sequential operational position an intermediate gas flow path through said conduit means.

7. Improvement according to claim 6 in which said heat-fusible material spray gun has separate gas conduit means for a combustible gas and a combustion supporting gas, with first, second and third valve means in each of said conduit means.

8. Improvement according to claim 7, including blast gas conduit means having first, second and third valve means connected therein.

9. Improvement according to claim 1 in which said valve means are arranged in series in said conduit, said first operating position of said first valve means being a shut position, said second operating position a full open position, said first operating position of said second valve means being a partial open position and said second operating position a full open position, said sequential operational position defining said full operational gas flow path being said second operating position for both said valve means, said alternate sequential operational position defining said reduced gas fiow path, being said second operating position for said first valve means and said first operating position for said second valve means.

10. Improvement according to claim 1 in which said first and second valve means are parallelly connected in parallel branches of said conduit means having difierent effective flow cross-sections.

11. Improvement according to claim 10 in which said parallel branches have difierent size flow orifices defining said different effective flow cross-sections.

12. Improvement according to claim 10 in which said parallel branches have additional adjustable valve means defining said different effective flow cross-sections.

13. Improvement according to claim 1 in which said first and second valve means are electrically operated valve means.

14. Improvement according to claim 1 in which said first and second valve means are solenoid operated valve means.

15. Improvement according to claim 1, including means for automatically actuating said valve means in sequence to their operational position defining said full operational gas fiow path for purging, actuating said valve means to their alternate sequential operational position defining said reduced gas flow path for lighting, and thereafter actuating said valve means to their operational position defining said full operational gas flow path for spraying.

16. Improvement according to claim 15 in which said first and second valve means are solenoid operated valve means and in which said means for automatically actuating said valve means include an electric timer motor.

17. Improvement according to claim 16, including electric ignition means for lighting said gun actuated by said electric timer motor after said valve means have been operated to their alternate sequential operational position defining said reduced gas flow path for lighting.

References Cited in the file of this patent UNITED STATES PATENTS 1,194,676 Slaw Aug. 15, 1916 2,197,979 Jones et a1 Apr. 23, 1940 2,255,189 Robinson et a1 Sept. 9, 1941 2,570,600 Sargrove Oct. 9, 1951 2,868,584 Faust Jan. 13, 1959 FOREIGN PATENTS 859,917 France Ian. 2, 1941 

1. IN A SPRAYING SYSTEM FOR SPRAYING HEAT-FUSIBLE MATERIAL INCLUDING A HEAT-FUSIBLE MATERIAL SPRAY GUN; GAS CONDUIT MEANS FOR SUPLYING AT LEAST ONE COMPONENT OF A COMBUSTIBLE GAS MIXTURE TO SAID GUN, AND VALVE MEANS FOR CONTROLLING THE FLOW OF GAS THROUGH SAID GAS CONDUIT MEANS, THE IMPROVEMENT WHICH COMPRISES SAID VALVE MEANS BEING COMPOSED OF FIRST VALVE MEANS HAVING A FIRST AND SECOND OPERATING POSITION CONNECTED IN SAID CONDUIT MEANS, SECOND VALVE MEANS HAVING A FIRST AND SECOND POSITION OF OPERATION CONNECTED IN SAID CONDUIT MEANS, SAID VALVE MEANS AND THEIR ASSOCIATED PORTIONS OF SAID CONDUIT MEANS DEFINING IN ONE SEQUENTIAL OPERATIONAL POSITION OF SAID FIRST AND SECOND VALVE MEANS, A FULL OPERATIONAL GAS FLOW PATH THROUGH SAID CONDUIT MEANS, AND IN AN ALTERNATE SEQUENTIAL OPERATIONAL POSITION OF SAID FIRST AND SECOND VALVE MEANS, A REDUCED GAS FLOW PATH THROUGH SAID CONDUIT MEANS AND IN A FURTHER ALTERNATE SEQUENTIAL OPERATIONAL POSITION SHUTTING OFF THE GAS FLOW THROUGH SAID CONDUIT MEANS, AND MEANS FOR ACTUATING SAID VALVE MEANS BETWEEN THEIR FIRST AND SECOND OPERATING POSITIONS TO ESTABLISH SAID ONE SEQUENTIAL OPERATIONAL POSITION, SAID ALTERNATE SEQUENTIAL OPERATIONAL POSITION AND SAID STILL FURTHER ALTERNATE SEQUENTIAL OPERATIONAL POSITION. 